Light transmitting flexible film electrical heater panels

A flexible light transmitting heater panel comprising, in combination:

• (1) a flexible light transmitting plastic film substrate;
• (2) a vacuum deposited transparent conductive layer on a first surface of the substrate selected from the group consisting of
• (i) a single lamina of tin oxide or indium tin oxide,
• (ii) a first lamina of indium oxide on the first surface of the substrate and a second lamina of indium tin oxide over the first lamina, or
• (iii) a first lamina of tin oxide, indium oxide or indium tin oxide on the first surface of the substrate, a second lamina of silver, platinum or palladium or an alloy of two or more of said metals over the first lamina, and a third lamina of tin oxide, indium oxide or indium tin oxide over the second lamina, the transparent conductive layer being in the range of about 200 to 5,000 Angstroms thick;
• (3) a first conductive electrode extending over a first edge portion of the transparent conductive layer, and a second conductive electrode extending over a second edge portion of the transparent conductive layer spaced from and opposite from the first edge portion thereof,
• the first and second electrodes each including a section for connecting the heater panel to an AC or DC power source;
• and in which
• (4) the transparent conductive layer covers a first portion of the first surface of the substrate, a pair of conductive traces are formed on another portion of the first surface of the substrate, and a chip thermistor is connected between the conductive traces for detecting substrate temperature when the heater panel is activated.